feat(switch): support claude-code install, smart runtime warnings, .gitignore propagation

- switch.py v1.2: `claude-code --project-dir` now copies skills (was error before)
- Skip runtime conversion for single-runtime skills (e.g. img-grid stays python)
- Distinguish info ("Python-версия не предусмотрена") from real missing-file warnings
- Print .gitignore recommendations for target project on install
- Copy root-level .gitignore from skills dir during install
- Interactive mode asks project path for all platforms, not just claude-code
- Add .gitignore in skills root (__pycache__/) and web-test/ (node_modules, *.png, *.mp4)
- Sync root .gitignore with all 13 platforms from PLATFORMS registry

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

.claude/skills/web-test/.gitignore

@@ -0,0 +1,4 @@
+scripts/node_modules/
+.browser-session.json
+*.png
+*.mp4